The present invention relates to novel DC-88A derivatives. The derivatives have an excellent antitumor activity and are useful as antitumor agents.
WO 87/06265 (EP-A-0271581) discloses DC-88A produced by microorganisms belonging to the genus Streptomyces exhibits not only an antibacterial activity against various bacteria but also an antitumor activity against lymphocytic leukemia P388, etc.
DC-88A has the following structure. ##STR4##
DC-89A1 which is a compound having a structure similar to DC-88A is disclosed in WO87/06265; DC-89A2, DC-89B1 and DC-89B2 are described in Japanese Patent Application No. 182866/88.
DC-89A1, DC-89A2, DC-89B1 and DC-89B2 have the following structures. ##STR5## DC-89A1: X=--CH.sub.2 --, Y=Cl DC-89A2: X=single bond, Y=--CH.sub.2 Cl
DC-89B1: X=--CH.sub.2 --, Y=Br PA0 DC-89B2: X=single bond, Y=--CH.sub.2 Br
These compounds show an antibacterial activity against various bacteria and an antitumor activity against lymphocytic leukemia P388, etc.
Further, in commonly owned U.S. patent application filed on Aug. 11, 1989, which corresponds to European Patent Application No. 89 114 896.7, DC-88A derivatives are described.
CC-1065 and its derivatives which are structurally similar to DC-88A and exhibit an antitumor activity are also disclosed in U.S. Pat. No. 4,169,888; Japanese Published Unexamined Patent Application No. 64695/79; EP-A-0154445, Japanese Published Unexamined Patent Application No. 193989/85; and WO 88/04659.